Multi-speed bicycle transmission

ABSTRACT

A multi-speed bicycle transmission having a housing including spaced, opposing face plates, with each face plate having a pedal shaft opening and a secondary shaft opening. A pedal shaft is rotatably disposed within the pedal shaft openings of the face plates, and a secondary shaft is disposed within the secondary shaft openings. As such, the secondary shaft is spaced from, and parallel to, the pedal shaft. A pedal shaft set of gears are mounted on the pedal shaft between the face plates. The pedal shaft set of gears include: (1) a first set of pedal shaft gears mounted on the pedal shaft, (2) a second set of pedal shaft gears rotatably mounted on the pedal shaft, and (3) a third set of pedal shaft gears rotatably mounted on the pedal shaft including first means for selective driving engagement with the second set of pedal shaft gears. The third set of pedal shaft gears including a drive gear means such as a sprocket for engaging a drive chain. A secondary shaft set of gears are mounted on the secondary shaft between the face plates.

FIELD OF THE INVENTION

The present invention relates generally to bicycle transmissions, and inparticular to multi-speed bicycle transmissions.

BACKGROUND OF THE INVENTION

Bicycles have been used for transportation for many years. Recently,bicycles have been increasingly utilized for exercise and healthreasons. A such, there are many different types of bicycles fordifferent purposes such as racing, traversing unpaved train and touring.

Many bicycles include multi-speed transmissions to enhance theiroperation over different types of train. Existing bicycle transmissionsare generally derailleur type, manually controlled by a cable connectedto a shift lever. Moving the shift lever changes the cable tension andmoves the derailleur and a drive chain from one gear to another gear.With different gearing ratios, different pedaling efforts and speeds areaccomplished.

A disadvantage of such transmissions is that shifting gears cannot beaccomplished without rotation of the gears. As such, proper gearshifting can only be performed when the bicycle is in motion, and arider cannot shift gears when stopped. This is particularly problematicin cases where before stopping the bicycle transmission has been shiftedto higher gears for high speed travel. Then when the rider stops, therider must exert a large amount of pedaling force to start the bicyclemoving again. Since the transmission requires rotation of thetransmission gears by a forward motion of the bicycle, the rider cannotdown shift the transmission to reduce the pedaling effort required tostart the bicycle moving again.

Another disadvantage of such conventional transmissions is that thegears are exposed to the elements and road dirt, leading to prematurewear and requiring frequent maintenance.

There is therefore a need for a multi-speed transmission for a bicyclewhich can be shifted while the bicycle is stationary. There is also aneed for such a transmission to require infrequent maintenance withoutpremature wear and tear.

BRIEF SUMMARY OF THE INVENTION

The present invention satisfies these needs. In one embodiment thepresent invention provides a multi-speed transmission for bicycles,comprising: (a) a housing including spaced, opposing face plates, eachface plate having a pedal shaft rotatably disposed within said pedalshaft openings; (c) a secondary shaft disposed within said secondaryshaft openings, wherein the secondary shaft is spaced from the pedalshaft and substantially parallel thereto; (d) a pedal shaft set of gearsmounted on the pedal shaft between the face plates, comprising: (1) afirst set of pedal shaft gears mounted on the pedal shaft (2) a secondset of pedal shaft gears rotatably mounted on the pedal shaft, and (3) athird set of pedal shaft gears rotatably mounted on the pedal shaftincluding first means for selective driving engagement with the secondset of pedal shaft gears, the third set of pedal shaft gears including adrive gear means; (e) a secondary shaft set of gears mounted on thesecondary shaft between the face plates, comprising: (1) a first set ofsecondary shaft gears mounted on the secondary shaft, and (2) a secondset of secondary shaft gears rotatably mounted on the secondary shaftincluding second means for selective driving engagement with the firstset of secondary shaft gears; (f) a primary set of pinion gearsrotatably attached to means for selectively engaging each pinion gearbetween the first set of pedal shaft gears and the first set ofsecondary shaft gears; and (g) a permanent pinion gear engaged betweenthe second set of pedal shaft gears and the second set of secondaryshaft gears.

In operation, when one of the primary pinion gears is engaged betweenthe first set of pedal shaft gears and the first set of secondary shaftgears, applying rotary torque to the pedal shaft causes: (1) the firstset of pedal shaft gears to rotate the first set of secondary shaftgears via the engaged primary pinion gear, (2) the first set ofsecondary shaft gears rotate the second set of secondary shaft gears,(3) the second set of secondary shaft gears rotate the second set ofpedal shaft gears via the permanent pinion gear, and (4) the second setof pedal shaft gears rotate the third set of pedal shaft gears includingsaid drive gear means. As such, advantageously, a multi-speedtransmission according to the present invention can be shifted up ordown without rotation of the transmission gears. Further, the housingcan encapsulate most of the transmission gear and protected them fromthe elements and road dirt.

As such, a bicycle transmission according to the present inventionprovides multi-speed transmission for a bicycle which can be shiftedwhile the bicycle is stationary. The transmission requires infrequentmaintenance without premature wear and tear. Further, the transmissionprovides for changing gears without slipping of the gears or the drivechain. This feature also reduces gear change noise, and increases thelife of the drive chain.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the presentinvention will become better understood with regard to the followingdescription, appended claims and accompanying drawings where:

FIG. 1 shows a schematic side elevation view of an embodiment of amulti-speed transmission according to the present invention, wherein aprimary pinion gear is engaged;

FIG. 2 shows a schematic front elevation view, partially cut away andsectioned, of the transmission of FIG. 1;

FIG. 3 shows the transmission of FIG. 1 wherein another primary piniongear is engaged;

FIG. 4 shows a schematic front elevation view, partially cut away andsectioned, of the transmission of FIG. 3;

FIG. 5 shows the transmission of FIG. 1 wherein another primary piniongear is engaged;

FIG. 6 shows a schematic front elevation view, partially cut away andsectioned, of the transmission of FIG. 5;

FIG. 7 shows the transmission of FIG. 1 wherein another pinion gear isengaged; and

FIG. 8 shows a schematic front elevation view, partially cut away andsectioned, of the transmission of FIG. 7.

FIG. 9 shows a partial perspective view of the transmission of FIG. 1illustrating gear engagement means for the primary pinion gears,

FIG. 10 shows a partial exploded view of the transmission of FIG. 1illustrating the gear sets;

FIG. 11 shows a perspective view of a primary pinion gear andcorresponding engagement means in transmission of FIG. 1;

FIG. 12 shows a perspective view of a cam mechanism cooperating with theengagement means of the primary pinion gears in transmission of FIG. 1;

FIG. 13 is a perspective view of the primary pinion gears intransmission of FIG. 1;

FIG. 14 is a partial perspective view of the gear sets and primarypinion gears with corresponding engagement means and cam mechanism intransmission of FIG. 1;

FIG. 15 shows another partial perspective view of the gear sets andprimary pinion gears with corresponding engagement means and cammechanism in transmission of FIG. 1;

FIG. 16 shows a schematic side elevation view of another embodiment of amulti-speed transmission according to the present invention, wherein anauxiliary pinion gear is engaged;

FIG. 17 shows a schematic front elevation view, partially cut away andsectioned, of the transmission of FIG. 16;

FIG. 18 shows a schematic side elevation view of another embodiment of amulti-speed transmission according to the present invention, wherein twoauxiliary pinion gear is engaged;

FIG. 19 shows a schematic front elevation view, partially cut away andsectioned, of the transmission of FIG. 18;

FIG. 20 is a partial perspective view of the transmission of FIG. 16showing the gear sets;

FIG. 21 is a partial perspective view of the transmission of FIG. 16showing the transmission gears and the auxiliary pinion gear engagementmeans, wherein neither auxiliary gear is engaged;

FIG. 22 shows a side perspective view of the auxiliary pinion gears andcorresponding support arms;

FIG. 23 shows a perspective view of an auxiliary pinion gear selectionmeans in transmission of FIG. 16;

FIG. 24 shows another partial perspective view of the transmission ofFIGS. 16-17 wherein one auxiliary pinion gear is selected;

FIG. 25 shows another partial perspective view of the transmission ofFIG. 16 illustrating the secondary shaft gears; and

FIG. 26 shows another partial perspective view of the transmission ofFIGS. 18-19 wherein both auxiliary pinion gears are engaged.

DETAILED DESCRIPTION OF THE INVENTION

Referring FIG. 1-15, in a preferred embodiment a multi-speed bicycletransmission 10 according to the present invention comprises a housing12 including spaced, opposing face plates 14, with each face plate 14having a pedal shaft opening 16 and a secondary shaft opening 18. Apedal shaft 20 is rotatably disposed within the pedal shaft openings 16of the face plates 14, and a secondary shaft 22 is disposed within thesecondary shaft openings 18. As such, the secondary shaft 22 is spacedfrom, and parallel to, the pedal shaft 20.

A pedal shaft set of gears 24 are mounted on the pedal shaft 20 betweenthe face plates 14. The pedal shaft set of gears 24 include: (1) a firstset of pedal shaft gears 26 mounted on the pedal shaft 20, (2) a secondset of pedal shaft gears 30 rotatably mounted on the pedal shaft 20, and(3) a third set of pedal shaft gears 32 rotatably mounted on the pedalshaft 20 including first means 34 for selective driving engagement withthe second set of pedal shaft gears 30. The third set of pedal shaftgears 32 including a drive gear means 36 such as a sprocket 38 forengaging a drive chain.

A secondary shaft set of gears 40 are mounted on the secondary shaft 22between the face plates 14. The secondary shaft set of gears 40 include:(1) a first set of secondary shaft gears 42 mounted on the secondaryshaft 22, and (2) a second set of secondary shaft gears 44 rotatablymounted on the secondary shaft 22 including second means 46 forselective driving engagement with the first set of secondary shaft gears42. Further, a set of primary pinion gears 48 are rotatably attached toa means 50 for selectively engaging each pinion gear 48 between thefirst set of pedal shaft gears 26 and the first set of secondary shaftgears 40. A permanent pinion gear 52 is engaged between the second setof pedal shaft gears 30 and the second set of secondary shaft gears 44.The transmission 10 can further include third means 28 for selectivedriving engagement of the first set of pedal shaft gears 26 with thepedal shaft 20.

As shown in FIG. 11, the permanent gear 52 is rotatably attached to adistal end 113 of a support arm 111. The support arm 111 includesopenings 115 and 117 corresponding to the member 109 and the shaft 102,respectively, for fixedly attaching the support arm 111 to the housing12 via the member 109 and the shaft 102 as illustrated in FIG. 11.

When one of the primary pinion gears 48 is engaged between the first setof pedal shaft gears 26 and the first set of secondary shaft gears 42,applying forward rotary torque to the pedal shaft 20 causes: (1) thefirst set of pedal shaft gears 26 to rotate the first set of secondaryshaft gears 42 via the engaged primary pinion gear 48, (2) the first setof secondary shaft gears 42 rotate the second set of secondary shaftgears 44, (3) the second set of secondary shaft gears 44 rotate thesecond set of pedal shaft gears 30 via the permanent pinion gear 52, and(4) the second set of pedal shaft gears 30 rotate the third set of pedalshaft gears 32 including said drive gear means 34. The drive gear means36 can include a pedal drive sprocket 38 for engaging and driving drivechain means connectable to a rear drive wheel of a bicycle.

In the embodiment of the invention shown in the drawings, the first setof pedal shaft gears 26 comprises two integral gears 54, 56 havingdifferent gearing ratios. For example, the gear 54 has 24 teeth and thegear 56 has 22 teeth. The second set of pedal shaft gears 30 comprisestwo integral gears 58, 60 having different gearing ratios. The gear 58has 18 teeth and the gear 60 has 24 teeth. The third set of pedal shaftgears 32 comprises two integral gears 62, 64 having different gearingratios. The gear 62 has 16 teeth and the gear 64 can comprise thesprocket 38 and have 16 or 18 teeth. The first set of secondary shaftgears 42 comprises four integral gears 66, 68, 70, 72 having differentgearing ratios. The gear 66 has 16 teeth, the gear 68 has 19 teeth, thegear 70 has 22 teeth and the gear 72 has 24 teeth. The second set ofsecondary shaft gears 44 comprises two integral gears 74, 76 havingdifferent gearing ratios. The gear 74 has 16 teeth and the gear 76 has24 teeth. Further the permanent pinion gear 52 has 18 teeth.

The primary pinion gears 48 include four pinion gears 78, 80, 82, 84which can have different gearing ratios. In one example, the pinion gear78 has 18 teeth, the pinion gear 80 has 18 teeth, the pinion gear 82 has18 teeth and the pinion gear 84 has 18 teeth. The means 50 forselectively engaging the primary pinion gears 48 comprises a set of fourspring loaded arms 86, 88, 90, 92 corresponding to the pinion gears 78,80, 82, 84, respectively, wherein each of the arms 86, 88, 90, 92 has aproximal end 94 pivotally attached to the housing 12 via a member 109,and a distal end 96 to which one of the corresponding pinion gears 78,80, 82, 84 is rotatably attached. Each of the arms 86, 88, 90, 92 has afirst pivot position where one of a corresponding pinion gears 78, 80,82, 84 is engaged as described above, and a second pivot position whereone of a corresponding pinion gears 78, 80, 82, 84 is disengaged.

Referring specifically to FIGS. 1-9, 12, 14, 15, a cam shaft 102 isrotatably attached between the two face plates 14. A set of cams 101,comprising four cams 104, 106, 108, 110 are mounted on the cam shaft102, wherein the four cam 104, 106, 108, 100 correspond to said fourarms 86, 88, 90, 92, respectively. Each of the cams 104, 106, 108, 110comprises a disk 112 with a perimeter depression 114, wherein anextension portion 116 of the proximal end 94 of one of a correspondingarms 86, 88, 90, 92 is urged on the perimeter of the disk 112 by thespring loaded arm. For each of the arms 86, 88, 90, 92, when theextension portion 116 engages the depression 114 of the disk 112, thearm is pivoted to the second pivot position where the correspondingpinion gear to attached to the arm is disengaged, otherwise, the arm ispivoted to the first pivot position where the pinion gear is engaged.The depressions 114 on the cams 104, 106, 108, 110 are out of phase,such that as the cam shaft 102 rotates, only the extension portion 116of one arm engages a corresponding cam's depression 114 at a time,whereby only one of the pinion gears 78, 80, 82, 84 is selected at atime. The camshaft 102 can be rotated for selectively engaging thepinion gears 78, 80, 82, 84 via a cable operated pulley 118 mounted onthe cam shaft 102.

Referring specifically to FIGS. 1-2, when the first primary pinion gear78 is selected, the first primary pinion gear 78 is engaged between thegear 54 of the first set of pedal shaft gears 26 and the gear 66 of thefirst set of secondary shaft gears 42. Applying forward rotary torque tothe pedal shaft 20 causes: (1) the gear 54 of the first set of pedalshaft gears 26 to rotate the gear 66 of the first set of secondary shaftgears 42 via the engaged primary pinion gear 78, (2) the first set ofsecondary shaft gears 42 rotates the second set of secondary shaft gears44, (3) the gear 74 of the second set of secondary shaft gears 42rotates the gear 60 of the second set of pedal shaft gears 30 via thepermanent pinion gear 52, and (4) the second set of pedal shaft gears 30rotates the gear 62 of the third set of pedal shaft gears 32 includingsaid drive gear means 36.

Referring specifically to FIGS. 3-4, when the second primary pinion gear80 is selected, the second primary pinion gear 80 is engaged between thegear 54 of the first set of pedal shaft gears 26 and the gear 68 of thefirst set of secondary shaft gears 42. Applying forward rotary torque tothe pedal shaft 20 causes: (1) the gear 54 of the first set of pedalshaft gears 26 to rotate the gear 68 of the first set of secondary shaftgears 42 via the engaged primary pinion gear 80, (2) the first set ofsecondary shaft gears 42 rotates the second set of secondary shaft gears44, (3) the gear 74 of the second set of secondary shaft gears 44rotates the gear 60 of the second set of pedal shaft gears 30 via thepermanent pinion gear 52, and (4) the second set of pedal shaft gears 30rotates the third set of pedal shaft gears 32 including said drive gearmeans 36.

Referring specifically to FIGS. 5-6, when the third primary pinion gear82 is selected, the third primary pinion gear 82 is engaged between thegear 54 of the first set of pedal shaft gears 26 and the gear 70 of thefirst set of secondary shaft gears 42. Applying forward rotary torque tothe pedal shaft 20 causes: (1) the gear 54 of the first set of pedalshaft gears 26 to rotate the gear 70 of the first set of secondary shaftgears 42 via the engaged primary pinion gear 82, (2) the first set ofsecondary shaft gears 42 rotates the second set of secondary shaft gears44, (3) the gear 74 of the second set of secondary shaft gears 44rotates the gear 60 of the second set of pedal shaft gears 30 via thepermanent pinion gear 52, and (4) the second set of pedal shaft gears 30rotates the third set of pedal shaft gears 32 including said drive gearmeans 36.

And, referring specifically to FIG. 7-8, when the fourth primary piniongear 84 is selected, the fourth primary pinion gear 84 is engagedbetween the gear 56 of the first set of pedal shaft gears 26 and thegear 72 of the first set of secondary shaft gears 42. Applying forwardrotary torque to the pedal shaft 20 causes: (1) the gear 54 of the firstset of pedal shaft gears 26 to rotate the gear 72 of the first set ofsecondary shaft gears 42 via the engaged primary pinion gear 84, (2) thefirst set of secondary shaft gears 42 rotates the second set ofsecondary shaft gears 44, (3) the gear 74 of the second set of secondaryshaft gears 44 rotates the gear 60 of the second set of pedal shaftgears 30 via the permanent pinion gear 52, and (4) the second set ofpedal shaft gears 30 rotates the third set of pedal shaft gears 32including said drive gear means 36.

The required pedaling effort decreases as each of the primary piniongears 78, 80, 82, and 84 are is individually engaged in turn. As such,the required pedaling effort when the pinion gear 78 is engaged ishigher than when pinion gear 80 is engaged. When the pinion gear 80 isengaged, the required pedaling effort is higher than when the piniongear 82 is engaged. And, when the pinion gear 82 engaged, the pedalingeffort is higher than when the pinion gear 84 is engaged. A higherpedaling effort provides more speed for the bike, and a lower pedalingeffort provides less speed for the bike. Typically higher pedalingeffort is selected for higher bike speed on level or down hill roads,where as lower pedaling effort is selected for lower bike speed onuphill roads.

The first means 28 for selective driving engagement of the first set ofpedal shaft gears 26 with the pedal shaft 20 comprises pawl meanseffectively subject to compressive stress only during forward rotativedisplacement of the pedal shaft 20. The second means 34 for selectivedriving engagement of the third set of pedal shaft gears 32 with thesecond set of pedal shaft gears 30 comprises pawl means effectivelysubject to compressive stress only during forward rotative displacementof the pedal shaft 20. And, the third means 46 for selective drivingengagement of the second set of secondary shaft gears 44 with the firstset of secondary shaft gears 42 comprises pawl means effectively subjectto compressive stress only during forward rotative displacement of thepedal shaft 20. Said pawls means are well known by the practitioners inthe art and so are not described herein.

Referring to FIGS. 16-26, the transmission 10 further comprises a set ofauxiliary pinion gears 119 including a first pinion gear 122 rotatablyattached to first engagement means 123 for selectively engaging thefirst pinion gear 122 between the first set of secondary shaft gears 42and the second set of pedal shaft gears 30. The auxiliary gears 119further includes a second pinion gear 120 rotatably attached to secondengagement means 121 for selectively engaging the second pinion gear 120between the second set of secondary shaft gears 44 and the third set ofpedal shaft gears 32. The first and second pinion gears 122 and 120 canbe of the same or different size and/or gearing rations.

Referring specifically to FIGS. 16-19, 21, 22, 24, 25 and 26, in oneembodiment, the first engagement means 123 comprises a spring loaded armhaving a proximal end 125 pivotally attached to the housing via a member127, and a distal end 129 to which the first auxiliary pinion gear 122is rotatably attached, said arm having a first pivot position where thefirst auxiliary pinion gear 122 is engaged, and a second pivot positionwhere the first auxiliary pinion gear 122 is disengaged. Further, thesecond engagement means 121 comprises a similar spring loaded arm havinga proximal end pivotally attached to the housing, and a distal end towhich the second auxiliary pinion 120 gear is rotatably attached, saidarm having a first pivot position where the second auxiliary pinion gear120 is engaged, and a second pivot position where the second auxiliarypinion gear 120 is disengaged.

Referring specifically to FIGS. 21-26, the transmission 10 can furthercomprises a pinion gear selection means 133 for controlling said firstand second engagement means, the pinion gear selection means 133 having:(i) a first control position whereby the first and the second auxiliarypinion gears 122, 120 are engaged, (ii) a second control positionwhereby the first and the second auxiliary pinion gears 122, 120 aredisengaged, and (iii) a third control position whereby the firstauxiliary pinion gear 122 is disengaged, and the second auxiliary piniongear 120 is engaged.

In one embodiment, the pinion gear selection means 133 comprises a camshaft 135 rotatably attached between the two face plates 14. Two cams137, 139 are mounted on the cam shaft 135, wherein the two cams 137, 139correspond to said two arms 123, 121, respectively. Each of the cams137, 139 comprises a partial disk 140 with a perimeter depression 142,wherein an extension portion 144 of the proximal end 144 of one of acorresponding arms 123, 121, is urged on the perimeter of the disk 140by the spring loaded arm. For each of the arms 123, 121, when theextension portion 144 engages the depression 142 of the disk 140, thearm is pivoted to the second pivot position where the correspondingpinion gear attached to the arm is disengaged, otherwise, the arm ispivoted to the first pivot position where the corresponding pinion gearis engaged. The depressions 142 on the cams 137, 139 are phases, suchthat as the cam shaft 135 rotates: (i) in the first control position thefirst and the second auxiliary pinion gears 122, 120 are engaged, (ii)in the second control position the first and the second auxiliary piniongears 122, 120 are disengaged, and (iii) in the third control positionthe first auxiliary pinion gear 122 is disengaged, and the secondauxiliary pinion gear 120 is engaged.

The first engagement means 123 engages the first pinion gear 122 betweenthe gear 72 of the first set of secondary shaft gears 42, and gear 58 ofthe second set of pedal shaft gears 30. The second engagement means 121engages the second pinion gear 120 between the gear 76 of the second setof secondary shaft gears 44, and the gear 62 of the third set of pedalshaft gears 32.

Referring specifically to FIGS. 16-17, torque from pedal shaft 20rotates gear set 26 which applies torque to gear set 42 via pinion gears42. In the example shown in FIG. 16-17, the pinion gear 78 is engagesbetween the gears 54 and 42, where torque from pedal shaft to the gear54 rotates the gear set 42 via the pinion gear 78. Rotation of gear set42 then rotates gear set 44. The permanent gear 52 is always engagedbetween the gear set 44 and the gear set 30. Specifically, gear 52engages between the gear 74 and the gear 60, and transfers torque fromthe gear 74 of the gear set 44 to the gear 60 of gear set 30, rotatingthe gear set 30. When the pinion gear 120 engages the gears 76 and 62,torque from the gear 76 rotated the gear 62 via the pinion gear 120,whereby the gear 62 rotates faster than the gear 60. As such, the gear60 rotates without applying any torque by skipping, and the gear 62applies torque to, and rotates, the gear 38. With pinion gear 78engaged, when the pinion gear 120 is engaged, the pedaling effort isincreased. This provides higher pedal effort and a higher speed for thebike.

Referring specifically to FIGS. 18-19, torque from pedal shaft 20rotates gear set 26 which applies torque to gear set 42 via pinion gears42. In the example shown in FIG. 18-19, the pinion gear 78 is engagesbetween the gears 54 and 42, where torque from pedal shaft to the gear54 rotates the gear 42 via the pinion gear 78. With the pinion gear 122is engaged between the gear 72 of the gear set 42, and the gear 58 ofthe gear set 30, torque from the gear 72 rotates the gear 58. Rotationof gear 58 rotates the gear set 30 and therefore rotates the gear 60.Because the permanent gear is engaged between the gear 60 and the gear74, torque from the gear 60 rotates the gear 74 via the permanent gear52. Rotation of the gear 74 rotates the gear set 44 and thereforerotates the gear 76. Torque from gear 76 rotates the gear 62 via thepinion gear 120 engaged therebetween. Rotation of the gear 62 rotatesthe gear set 32 and therefore rotates the gear 38.

In FIG. 18-19, the permanent gear 52 rotates in the opposite directionof that in FIGS. 10-11 due to transfer of torque from the gear 74 to thegear 58 via the pinion gear 122. With the pinion gears 78 and 120engaged, when the pinion gear 122 is engaged, the pedaling effort isincreased, providing for higher bike speed. As such, when the piniongears 78, 120 and 122 are engaged, the transmission requires the highestpedaling effort and provides most speed for the bike. When only thepinion gear 84 is engaged, the transmission requires the lowest pedalingeffort and provides the lowest bike speed.

The selection means 133 can be controlled via a cable 147 from abicycles break lever, wherein the cable 147 is attached to the lever 146for rotating the shaft 135. In one embodiment, under normal gearselection operation, both of the gears 120 and 122 are engaged. Thebreak pedal is pulled full stroke for breaking, both of the gears 120and 122 are disengaged. In another embodiment, a select lever can beincluded on the break lever to enable the following gear selectionmodes: (1) when the select lever is in a first position (e.g., pulledback relative to break lever), after the break lever is released, bothpinion gears 120 and 122 are engaged again; (2) when the select level isin a second position (e.g., aligned with break lever, after the breaklever is released, both the pinion gears 120 and 122 are disengaged; and(3) when the select lever is in a third position (e.g., pushed forwardrelative to the break lever), after the break lever is released, onlyone auxiliary pinion gear (e.g., gear 122) is disengaged, the otherauxiliary pinion gear is engaged again.

As shown in the drawings, the transmission 10 can include both theprimary pinion gears 48 and the auxiliary pinion gears 119 as describedabove, wherein a user can selectively and simultaneouslyengage/disengage the primary and secondary pinion gears 48, 119 asdescribed above.

Although the present invention has been described in considerable detailwith regard to the preferred versions thereof, other versions arepossible. Therefore, the appended claims should not be limited to thedescriptions of the preferred versions contained herein.

What is claimed is:
 1. A multi-speed transmission for bicycles,comprising: (a) a housing including spaced, opposing face plates, eachface plate having a pedal shaft opening and a secondary shaft opening;(b) a pedal shaft rotatably disposed within said pedal shaft openings;(c) a secondary shaft disposed within said secondary shaft openings,wherein the secondary shaft is spaced from the pedal shaft andsubstantially parallel thereto; (d) a pedal shaft set of gears mountedon the pedal shaft between the face plates, comprising: (1) a first setof pedal shaft gears mounted on the pedal shaft, (2) a second set ofpedal shaft gears rotatably mounted on the pedal shaft, and (3) a thirdset of pedal shaft gears rotatably mounted on the pedal shaft andincluding first means for selective driving engagement with the secondset of pedal shaft gears, the third set of pedal shaft gears including adrive gear means for engaging and driving; (e) a secondary shaft set ofgears mounted on the secondary shaft between the face plates,comprising: (1) a first set of secondary shaft gears mounted on thesecondary shaft, and (2) a second set of secondary shaft gears rotatablymounted on the secondary shaft and including second means for selectivedriving engagement with the first set of secondary shaft gears; (f) aset of primary pinion gears rotatably attached to means for selectivelyengaging each pinion gear between the first set of pedal shaft gears andthe first set of secondary shaft gears, wherein said means forselectively engaging the primary pinion gears comprises a set of armseach corresponding to said one of primary pinion gears, said each armhaving a proximal end pivotally attached to the housing, and a distalend to which said corresponding primary pinion gear is rotatablyattached, said arm having a first pivot position where said primarypinion gear is engaged, and a second pivot position where said primarypinion gear is disengaged; and (g) a permanent pinion gear engagedbetween the second set of pedal shaft gears and the second set ofsecondary shaft gears; wherein, when one of the primary pinion gears isengaged between the first set of pedal shaft gears and the first set ofsecondary shaft gears, applying rotary torque to the pedal shaft causes:(1) the first set of pedal shaft gears to rotate the first set ofsecondary shaft gears via the engaged primary pinion gear, (2) the firstset of secondary shaft gears rotate the second set of secondary shaftgears, (3) the second set of secondary shaft gears rotate the second setof pedal shaft gears via the permanent pinion gear, and (4) the secondset of pedal shaft gears rotate the third set of pedal shaft gearsthereby rotating said drive gear means.
 2. The multi-speed transmissionof claim 1, wherein the first set of pedal shaft gears comprises atleast two integral gears having different numbers of teeth.
 3. Themulti-speed transmission of claim 1, wherein the second set of pedalshaft gears comprises at least one gear.
 4. The multi-speed transmissionof claim 1, wherein the third set of pedal shaft gears comprises atleast two integral gears having different numbers of teeth.
 5. Themulti-speed transmission of claim 1, wherein the set of primary piniongears comprises at least two primary pinion gears.
 6. The multi-speedtransmission of claim 1, wherein the primary pinion gears have differentnumbers of teeth.
 7. The multi-speed transmission of claim 1, whereinthe first set of secondary shaft gears comprises at least two integralgears having different numbers of teeth.
 8. The multi-speed transmissionof claim 1, wherein the second set of secondary shaft gears comprises atleast one gear.
 9. The multi-speed transmission of claim 1 furtherincluding means for selective driving engagement of the first set ofpedal shaft gears with the pedal shaft comprising pawl means effectivelysubject to stress only during forward rotative displacement of saidpedal shaft.
 10. The multi-speed transmission of claim 9 wherein saidstress is compressive.
 11. The multi-speed transmission of claim 1wherein said first means for selective driving engagement of the thirdset of pedal shaft gears with the second set of pedal shaft gearscomprises pawl means effectively subject to stress only during forwardrotative displacement of said pedal shaft.
 12. The multi-speedtransmission of claim 11 wherein said stress is compressive.
 13. Themulti-speed transmission of claim 1 wherein said second means forselective driving engagement of the second set of secondary shaft gearswith the first set of secondary shaft gears comprises pawl meanseffectively subject to stress only during forward rotative displacementof said pedal shaft.
 14. The multi-speed transmission of claim 13wherein said stress is compressive.
 15. The multi-speed transmission ofclaim 1 wherein said drive gear means includes a pedal drive sprocket.